ALPL and hypophosphatasia: Mutational analysis revealed that FM1-1, FM1-2, and FM4-1 carried with compound heterozygous missense mutations, and the analysis of the 3D structural model showed that T141 and R136 were both located at the active site, indicating indirectly affect the function of TNSALP, which may be predicted to be dominant negative effect, suggesting the patients with moderate childhood HPP.